Figure 2. Generation of integration-free iPSCs from adult PBMNCs with episomal vectors.

(A) ALP staining of iPSCs at 4 weeks after nucleofection of PBMNCs with reprogramming factor-expressing episomal vectors. OS, OCT4 and SOX2; MK, MYC and KLF4; B, BCL-XL. PBMNCs were cultured for 4–8 days before nucleofection. 1×10⁶ PBMNCs were nucleofected and then seeded into each well. (B) Inclusion of BCL-XL increases PB reprogramming efficiency by up to 10-fold. PBMNCs were cultured for 4–8 days before nucleofection. ALP-positive iPSC colonies were enumerated at 3–4 weeks after nucleofection. Data are presented as mean ± SEM (n = 6). In all 3 conditions, BCL-XL significantly increased reprogramming efficiency. * indicates P<0.05. (C) iPSC are generated from PBMNCs expressing the myeloid lineage marker, CD33, but not lymphoid cells (CD3⁺ and CD19⁺ cells) in PBMNCs. ALP staining of iPSCs at 4 weeks after nucleofection of fractionated PBMNCs with episomal vectors OS+MK+B. CD33, myeloid marker; CD3, T cell marker; CD19, B cell marker. 1×10⁶ indicated cells were nucleofected and then seeded into each well. ALP staining was conducted at 4 weeks after nucleofection.